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When to Plant Spinach in Adair County, OK

Adair County, Oklahoma Zone 7b May

Your May game plan for Adair County, Oklahoma

We've pulled the most time-sensitive tasks for Adair County, Oklahoma this May and put them front and centre. Tackle them in order.

Avg. last frost April 7
Avg. first frost October 27
Soil temp (4") 66°F
Watering Low
Pest pressure Moderate
Daylight 13.9 hrs
  1. Indoor seed-starting week for spinach

    A seed-starting mix and a sunny window (or a grow light) are all you need. Keep soil warm — around 70°F — for fast germination.

  2. Basket week: spinach

    Check every 1–2 days. Many of these get tough or go to seed if you wait too long.

A few tasks this May that'll pay off in June
  • First harvests: spinach

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Spinach is a nutrient-packed cool-season green that grows quickly in spring and fall. It is rich in iron, vitamins, and antioxidants and excellent raw or cooked.

Adair County, Oklahoma is in USDA Zone 7b. The average last spring frost is April 7 and the first fall frost is October 27, giving you a growing season of approximately 203 days.

At an elevation of 486 feet, Adair County receives approximately 33.9 inches of rainfall annually with predominantly loam soil. Summer highs average 93°F, providing good warmth for Spinach during the growing season.

Adair County, OK (Zone 7b) Long season
203 days
Last Spring Frost April 7
203 growing days
First Fall Frost October 27
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Adair County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (111 days to spare)
Start indoors: Feb 21 Transplant: Mar 28 🍅 Harvest: May 2 – Jul 4
Recommended (50%) ✓ Fits season (105 days to spare)
Start indoors: Mar 3 Transplant: Apr 7 🍅 Harvest: May 12 – Jul 14
Safe Start (90%) ✓ Fits season (111 days to spare)
Start indoors: Mar 21 Transplant: Apr 25 🍅 Harvest: May 30 – Aug 1

Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.

Soil Compatibility in Adair County

How your county's soil matches Spinach's growing requirements.

Soil pH

Your soil pH (6.7–7.1) is within Spinach's preferred range (6.5–7.5).

Soil Texture

The loam soil in Adair County is excellent for Spinach — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.1%) — Spinach will thrive.

How to Plant Spinach

0.5"
Planting Depth
6"
Between Plants
12"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Spinach

7
successive plantings in your 203-day season

Sow every 4 weeks. Last sowing by Sep 07 to harvest before frost.

For a dedicated fall crop, sow by Aug 18.

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
0.7″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Spinach

Spinach needs approximately 0.7 inches of water per week (3" per month). Here's how your county's rainfall compares month by month.

Month Spinach Needs Rainfall You Supplement Action
Jan 1" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 2.4" 0" ❄️ Dormant
Apr 3" 4.2" 0" ✅ Rainfall sufficient
May 3" 4.5" 0" ✅ Rainfall sufficient
Jun 3" 5.5" 0" ✅ Rainfall sufficient
Jul 3" 4.1" 0" ✅ Rainfall sufficient
Aug 3" 3.6" 0" ✅ Rainfall sufficient
Sep 3" 3.1" 0" ✅ Rainfall sufficient
Oct 3" 2.4" 0.6" 💧 Light watering
Nov 1.2" 0" ❄️ Dormant
Dec 0.8" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Adair County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Spinach Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Spinach needs ~839 GDD — county provides 4,009 GDD Excellent fit

Spinach Planting Timeline — Adair County, OK

Spinach Planting Calendar

Activity When Date Range
Start Indoors March 3 Mar 3 – Mar 17
Transplant Outdoors April 7 Apr 7 – Apr 21
Direct Sow March 24 Mar 24 – Apr 14
Harvest May 12 May 12 – Jul 14
Fall Sowing August 18 Aug 18 – Sep 1

Plant 0.5" deep · 6" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors Direct Sow
April Transplant Outdoors Direct Sow
May Harvest
June Harvest
July Harvest
August Fall Sowing
September Fall Sowing
October
November
December
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Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

0.7"/week · Natural rainfall sufficient

📅 Days to Maturity

35–50 days

🧪 Soil pH

Needs 6.5–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 7b

📆 Growing Season

203 days in Adair County

Growing Tips for Spinach in Adair County

Direct sow Spinach outdoors after April 07 in Adair County when soil has warmed and frost danger has passed.

Summer highs in Adair County reach 93°F — grow Spinach as a spring or fall crop. Use shade cloth if planting in summer.

Your generous 203.0-day season in Adair County allows multiple plantings of Spinach. Sow every 17.0 days for continuous harvest.

General growing tips

Direct sow as soon as soil can be worked in spring. Plant in partial shade for summer crops to delay bolting. Succession plant every 2 weeks for continuous harvest.

Recommended Spinach Varieties for Adair County

Slow-bolting spinach for warm springs — best as fall crop here

Bloomsdale Long Standing Tyee Space

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

🌾 Save Your Own Spinach Seeds
Life Cycle Annual
Pollination Wind Pollinated
How to Collect Let plants bolt. Harvest seed stalks when seeds turn tan.
Storage Store airtight; viable 5 years at 35°F, under 45% humidity.

Wind pollinated — isolate 1/2 mile for purity. Easy to let bolt in heat.

Frequently Asked Questions

When should I plant Spinach in Adair County, OK?

Adair County is in Zone 7b with an average last frost of April 7. Plan your Spinach planting based on this frost date — see the calendar above for exact timing.

What planting zone is Adair County, OK?

Adair County, Oklahoma is in USDA Hardiness Zone 7b. The average last spring frost is April 7 and first fall frost is October 27.

🌱

Your Adair County Garden Planner — Free

A 24-page printable planner built for Adair County (Zone 7b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Adair County, OK. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.